Hi, Anastasia! > 28 авг. 2020 г., в 23:08, Anastasia Lubennikova > <a.lubennik...@postgrespro.ru> написал(а): > > 1) The first patch is sensible and harmless, so I think it is ready for > committer. I haven't tested the performance impact, though. > > 2) I like the initial proposal to make various SLRU buffers configurable, > however, I doubt if it really solves the problem, or just moves it to another > place? > > The previous patch you sent was based on some version that contained changes > for other slru buffers numbers: 'multixact_offsets_slru_buffers' and > 'multixact_members_slru_buffers'. Have you just forgot to attach them? The > patch message "[PATCH v2 2/4]" hints that you had 4 patches) > Meanwhile, I attach the rebased patch to calm down the CFbot. The changes are > trivial. > > 2.1) I think that both min and max values for this parameter are too extreme. > Have you tested them? > > + &multixact_local_cache_entries, > + 256, 2, INT_MAX / 2, > > 2.2) MAX_CACHE_ENTRIES is not used anymore, so it can be deleted. > > 3) No changes for third patch. I just renamed it for consistency.
Thank you for your review. Indeed, I had 4th patch with tests, but these tests didn't work well: I still did not manage to stress SLRUs to reproduce problem from production... You are absolutely correct in point 2: I did only tests with sane values. And observed extreme performance degradation with values ~ 64 megabytes. I do not know which highest values should we pick? 1Gb? Or highest possible functioning value? I greatly appreciate your review, sorry for so long delay. Thanks! Best regards, Andrey Borodin.
